1278321408 has 486 divisors, whose sum is σ = 4711933044. Its totient is φ = 332107776.

The previous prime is 1278321383. The next prime is 1278321413. The reversal of 1278321408 is 8041238721.

It is a super-2 number, since 2×1278321408² = 3268211244302204928, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 19079391 + ... + 19079457.

Almost surely, 2^1278321408 is an apocalyptic number.

1278321408 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1278321408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2355966522).

1278321408 is an abundant number, since it is smaller than the sum of its proper divisors (3433611636).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1278321408 is a wasteful number, since it uses less digits than its factorization.

1278321408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 1278321408 is about 35753.6209075389. The cubic root of 1278321408 is about 1085.2922140440.

It can be divided in two parts, 12783 and 21408, that added together give a triangular number (34191 = T₂₆₁).

The spelling of 1278321408 in words is "one billion, two hundred seventy-eight million, three hundred twenty-one thousand, four hundred eight".